High-nickel ternary positive electrode material having high thermal safety, preparation method therefor, and use thereof

Abstract

The present application provides a high-nickel ternary positive electrode material having high thermal safety. According to the high-nickel ternary positive electrode material provided in the present application, significant factors affecting the thermal safety of the ternary positive electrode material are identified by measuring a thermal conductivity K, a D104 value in XRD, and a porosity α of the material. In addition, corresponding materials are prepared by means of controlling these parameters and satisfying the relationship shown in Formula I for verification. Furthermore, the high-nickel ternary positive electrode material is improved by coating with a coating material having a low thermal conductivity. The thermal conductivity of the coated material is tested, and the results indicate that with an increase in the coating amount of the coating material, the thermal conductivity of the ternary positive electrode material is in overall decrease, and the ternary positive electrode material has a better thermal safety.

What is claimed is: 
     
         1 . A high-nickel ternary positive electrode material having high thermal safety, therein the high-nickel ternary positive electrode material has a chemical formula of:
   LiNi a Co b Mn c M d Q e O 2 ,   wherein 0.8<a<0.95, b<0.2,c<0.2,d<0.1,a+b+c+d+e=1,   M is a doping element, selected from one or more of Sr, Ti, Al, Zr, Y, Ba, Mg, or Mo,   Q is a coating element, selected from one or both of Sr or Ti,   the high-nickel ternary positive electrode material satisfies a relationship shown in Formula I:   
       
         
           
             
               
                 
                   
                     γ 
                     = 
                     
                       α 
                       * 
                       D 
                       ⁢ 
                       104 
                       / 
                       K 
                     
                   
                 
                 
                   
                     Formula 
                     ⁢ 
                         
                     I 
                   
                 
               
             
           
         
         in Formula I, 0.73≤γ≤14.00, γ is a thermal safety coefficient of the high-nickel ternary positive electrode material, α is a cross-sectional porosity of the high-nickel ternary positive electrode material, D104 is a parameter of the high-nickel ternary positive electrode material in a XRD test, and K is a thermal conductivity of the high-nickel ternary positive electrode material. 
       
     
     
         2 . The high-nickel ternary positive electrode material according to  claim 1 , wherein 45≤D104≤70. 
     
     
         3 . The high-nickel ternary positive electrode material according to  claim 1 , wherein 1% ≤α≤5%. 
     
     
         4 . The high-nickel ternary positive electrode material according to  claim 1 , wherein 0.1 W/(m·K)≤K≤0.6 W/(m·K). 
     
     
         5 . The high-nickel ternary positive electrode material according to  claim 1 , comprising a core, and a coating layer, and the coating layer has a thermal conductivity of ≤0.2 W/(m·K). 
     
     
         6 . A method for preparing the high-nickel ternary positive electrode material according to  claim 1 , comprising the following steps:
 A) mixing a ternary hydroxide precursor Ni a Co b Mn c (OH) 2 , a lithium source, and a compound containing the element M, and then sintering under an oxygen atmosphere to obtain a sintered product;   B) washing and drying the sintered product, mixing the sintered product with a compound containing the element Q, and then sintering under the oxygen atmosphere to obtain the high-nickel ternary positive electrode material.   
     
     
         7 . The method for preparing the high-nickel ternary positive electrode material according to  claim 6 , wherein 45≤D104≤70. 
     
     
         8 . The method for preparing the high-nickel ternary positive electrode material according to  claim 6 , wherein 1% ≤α≤5%. 
     
     
         9 . The method for preparing the high-nickel ternary positive electrode material according to  claim 6 , wherein 0.1W/(m·K)≤K≤0.6 W/(m·K). 
     
     
         10 . The method for preparing the high-nickel ternary positive electrode material according to  claim 6 , comprising a core, and a coating layer, and the coating layer has a thermal conductivity of ≤0.2 W/(m·K). 
     
     
         11 . The method according to  claim 6 , wherein the lithium source is selected from LiOH;
 the compound containing the element M is selected from one or more of Al(OH) 3 , Al 2 O 3 , SrO, TiO 2 , ZrO 2 , Zr(OH) 4 , Y 2 O 3 , BaCO 3 , MgO, or MoO 3 ;   the compound containing the element Q is selected from TiO 2 , SrO, or SrTiO 3 .   
     
     
         12 . The method according to  claim 6 , wherein in step A), the sintering is performed at a temperature of 740° C.-820°° C. for a time of 10-15 hours. 
     
     
         13 . The method according to  claim 6 , wherein in step B), the sintering is performed at a temperature of 350-500°° C. for a time of 8-12 hours. 
     
     
         14 . A lithium ion battery comprising the high-nickel ternary positive electrode material according to  claim 1 . 
     
     
         15 . A lithium ion battery comprising the high-nickel ternary positive electrode material prepared by the method according to  claim 6 .